OK, hopefully I'll get some schooling here but also I think it'd be nice t have a thread where we post hypothetical situations and the possible solutions. Maybe some of you have experienced them for real. Please share your answers.

Hypothetical situation:
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OK, so you're at the top of the route and you've just had your rest and shoot, you kick all your gear down the face. You've still got your rope, harness and belay 'biner. There's a rap ring at the top. How do you descend ? Assume the rope is long enough to do your pitch. Double rope.

Years ago when Stannard and I were climbing the West Face of Sentinel, I was leading the squeeze chimneys above the expanding flake traverse when, as a result of turning around and shifting the gear one too many times, I managed to drop a sling that had every one of our bongs on it.

The sling went down 300 feet and then snagged on a thumb-sized twig growing out of the rock. We tied our two ropes together, rappelled to the sling and retrieved it, jugged back up, and continued the climb.

Stannard demonstrating a high level of competence nailing the expanding flake traverse, just before I demonstrated an abysmally low level of competence by dropping all our wide gear on the next pitch.

Apparently, having one competent party member is enough to solve even major problems...

Why wouldn't a vessel with a vacuum in it be lighter than a vessel with helium in it.

Can't we fly blimps with a vacuum instead of helium??

What the devil does this have to do with dropped gear? Oh well...a vessel with a vacuum in it is indeed lighter than the same vessel with helium in it, but that's not the point. The vacuum-filled vessel has to withstand the load of air pressure from the outside, 15 psi, so the vessel walls have to be much stronger, hence probably also heavier, maybe too heavy for Archimedes...

Helium is lighter than air but can be used to pressurize the inside of the vessel so that the walls do not have to stand up to air pressure.

My favorite home science experiment as a kid was to fill an empty tin solvent can with water, heat it until just the moment when all the water boiled off, cap it and run some cold water on the outside. The can was filled with steam, the cold water caused the steam to condense, creating a partial vacuum, which was enough for air pressure to totally crush the can.